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2D Structure
Also known as: Hyoscine, (-)-hyoscine, 51-34-3, Scopine (-)-tropate, Scopine tropate, (-)-scopolamine
Molecular Formula
C17H21NO4
Molecular Weight
303.35  g/mol
InChI Key
STECJAGHUSJQJN-USLFZFAMSA-N
FDA UNII
DL48G20X8X

An alkaloid from SOLANACEAE, especially DATURA and SCOPOLIA. Scopolamine and its quaternary derivatives act as antimuscarinics like ATROPINE, but may have more central nervous system effects. Its many uses include an anesthetic premedication, the treatment of URINARY INCONTINENCE and MOTION SICKNESS, an antispasmodic, and a mydriatic and cycloplegic.
Scopolamine is an Anticholinergic. The mechanism of action of scopolamine is as a Cholinergic Antagonist.
1 2D Structure

2D Structure

2 Identification
2.1 Computed Descriptors
2.1.1 IUPAC Name
[(1R,2R,4S,5S)-9-methyl-3-oxa-9-azatricyclo[3.3.1.02,4]nonan-7-yl] (2S)-3-hydroxy-2-phenylpropanoate
2.1.2 InChI
InChI=1S/C17H21NO4/c1-18-13-7-11(8-14(18)16-15(13)22-16)21-17(20)12(9-19)10-5-3-2-4-6-10/h2-6,11-16,19H,7-9H2,1H3/t11?,12-,13-,14+,15-,16+/m1/s1
2.1.3 InChI Key
STECJAGHUSJQJN-USLFZFAMSA-N
2.1.4 Canonical SMILES
CN1C2CC(CC1C3C2O3)OC(=O)C(CO)C4=CC=CC=C4
2.1.5 Isomeric SMILES
CN1[C@@H]2CC(C[C@H]1[C@H]3[C@@H]2O3)OC(=O)[C@H](CO)C4=CC=CC=C4
2.2 Other Identifiers
2.2.1 UNII
DL48G20X8X
2.3 Synonyms
2.3.1 MeSH Synonyms

1. Boro Scopol

2. Boro-scopol

3. Hyoscine

4. Isopto Hyoscine

5. Kwells

6. Scoburen

7. Scopace

8. Scopoderm Tts

9. Scopolamine Cooper

10. Scopolamine Hydrobromide

11. Transderm Scop

12. Transderm V

13. Transderm-v

14. Travacalm Ho

15. Vorigeno

2.3.2 Depositor-Supplied Synonyms

1. Hyoscine

2. (-)-hyoscine

3. 51-34-3

4. Scopine (-)-tropate

5. Scopine Tropate

6. (-)-scopolamine

7. 6,7-epoxytropine Tropate

8. Hyosol

9. Atrochin

10. Atroquin

11. Isopto Hyoscine

12. Skopolamin

13. Transderm-scop

14. L-scopolamine

15. Epoxytropine Tropate

16. Scopolamine Hydrobromide

17. 6-beta,7-beta-epoxy-3-alpha-tropanyl S-(-)-tropate

18. Beldavrin

19. Scopamin

20. Kwells

21. Alpha-(hydroxymethyl)benzeneacetic Acid 9-methyl-3-oxa-9-azatricyclo(3.3.1.0(2.4))non-7-yl Ester

22. Hyosceine

23. Scop

24. Dl48g20x8x

25. Tropic Acid, Ester With Scopine

26. Chembl3084722

27. Chebi:16794

28. Euscopol

29. Isoscopil

30. Tranaxine

31. (1s,3s,5r,6r,7s)-6,7-epoxytropan-3-yl (2s)-3-hydroxy-2-phenylpropanoate

32. Hysco

33. Hyoscine Bromide

34. Scopace

35. Transderm Scop

36. Scopolamine Hcl

37. Boro-scopol

38. Hyoscine Hydrobromide

39. Scopolaminium Bromide

40. 1alphah,5alphah-tropan-3alpha-ol, 6beta,7beta-epoxy-, (-)-tropate (ester)

41. Scopolammonium Bromide

42. L-hyoscine Hydrobromide

43. See

44. (-)-scopolamine Bromide

45. L-scopolamine-hydrobromide

46. Scopolamine Bromide

47. (-)-hyoscine Hydrobromide

48. Scopoderm

49. Levo-duboisine

50. (+)-hyoscine

51. (1r,2r,4s,5s,7s)-9-methyl-3-oxa-9-azatricyclo[3.3.1.0(2,4)]non-7-yl (2s)-3-hydroxy-2-phenylpropanoate

52. Hyoscyine Hydrobromide

53. Atroscine Hydrobromide

54. Hydroscine Hydrobromide

55. Hydrobromicum, Scopolaminum

56. Unii-dl48g20x8x

57. Tropane Alkaloid

58. Hsdb 4074

59. 6.beta.,7.beta.-epoxy-1.alpha.h,5.alpha.h-tropan-3.alpha.-ol (-)-tropate (ester)

60. Einecs 200-090-3

61. Nsc61806

62. S-(-)-tropate

63. Scopolamine [mi]

64. Prestwick3_000877

65. Hyoscine [mart.]

66. Scopolamine [hsdb]

67. Hyoscine [who-dd]

68. Ec 200-090-3

69. Scopolamine [vandf]

70. 6beta,7beta-epoxy-3alpha-tropanyl S-(-)-tropate

71. Schembl16226

72. Bspbio_000953

73. Gtpl330

74. 6beta,7beta-epoxy-1alpha,5alpha-tropan-3alpha-ol

75. Hyoscine [ep Impurity]

76. Bpbio1_001049

77. Chembl569713

78. Hyoscine [ep Monograph]

79. Chembl1906925

80. Dtxsid6023573

81. Schembl22393238

82. Chebi:93572

83. Scopolamine [orange Book]

84. Hms2090n13

85. Hms3886l22

86. Scopolamine [usp Impurity]

87. Hy-n0296

88. Lsm-4015

89. Ac-968

90. Bdbm50263508

91. S9326

92. Zinc13118910

93. Akos025402477

94. Tropic Acid, 9-methyl-3-oxa-9-azatricyclo(3.3.1.0(sup 2,4))non-7-yl Ester

95. Zinc100037020

96. Zinc101147375

97. Ccg-267504

98. Cs-6609

99. Db00747

100. 3-oxa-9-azatricyclo(3.3.1.0(sup 2,4))nonan-7-ol, 9-methyl-, Tropate (ester)

101. 3-oxa-9-azatricyclo(3.3.1.o(sup 2,4))nonan-7-ol, 9-methyl-, Tropate (ester)

102. Smp1_000270

103. Ncgc00024357-04

104. Ncgc00024357-05

105. (1r,2r,4s,5s,7s)-9-methyl-3-oxa-9-azatricyclo[3.3.1.0~2,4~]non-7-yl (2s)-3-hydroxy-2-phenylpropanoate

106. Ab00429689

107. Ab00429689-30

108. Ab00429689-31

109. Ab00429689_32

110. Atropine Sulfate Impurity F [ep Impurity]

111. Q337188

112. (methyl[?]yl) (2s)-3-hydroxy-2-phenyl-propanoate

113. Brd-k89923877-003-02-4

114. Q27165268

115. (1r,2r,4s,5s,7s)-9-methyl-3-oxa-9-azatricyclo(3.3.1.02,4)non-7-yl (2s)-3-hydroxy-2-phenylpropanoate

116. (1r,2r,4s,5s,7s)-9-methyl-3-oxa-9-azatricyclo[3.3.1.0^{2,4}]nonan-7-yl (2s)-3-hydroxy-2-phenylpropanoate

117. (1r,2r,4s,5s,7s)-9-methyl-3-oxa-9-azatricyclo[3.3.1.02,4]non-7-yl (2r)-3-hydroxy-2-phenylpropanoate

118. (1r,2r,4s,5s,7s)-9-methyl-3-oxa-9-azatricyclo[3.3.1.02,4]nonan-7-yl (2s)-3-hydroxy-2-phenylpropanoate

119. (1r,2r,4s,5s,7s)-9-methyl-3-oxa-9-azatricyclo[3.3.1.02,4]nonan-7-yl (s)-3-hydroxy-2-phenylpropanoate

120. [(1r,2r,4s,5s)-9-methyl-3-oxa-9-azatricyclo[3.3.1.02,4]nonan-7-yl] (2s)-3-hydroxy-2-phenylpropanoate

121. [7(s)-(1.alpha.,2.beta.,4.beta.,5.alpha.,7.beta.)]-.alpha.-(hydroxymethyl)benzeneacetic Acid 9-methyl-3-oxa-9-azatricyclo-[3.3.1.0^2,4]non-7-yl Ester

122. Benzeneacetic Acid, .alpha.(hydroxymethyl)-,(1.alpha.,2.beta.,4.beta.,5.alpha.,7.beta.)-9-methyl-3-oxa-9-azatricyclo(3.3.1.02,4)non-7-yl Ester, (.alpha.s)-

123. Benzeneacetic Acid, .alpha.-(hydroxymethyl)-, 9-methyl-3-oxa-9-azatricyclo(3.3.1.02,4)non-7-yl Ester, (7(s)-(1.alpha.,2.beta.,4.beta.,5.alpha.,7.beta.))-

124. Benzeneacetic Acid, Alpha-(hydroxymethyl)-, (1alpha,2beta,4beta,5alpha,7beta)-9-methyl-3-oxa-9-azatricyclo(3.3.1.02,4)non-7-yl Ester, (alphas)-

125. Benzeneacetic Acid, Alpha-(hydroxymethyl)-, 9-methyl-3-oxa-9-azatricyclo(3.3.1.02,4)non-7-yl Ester, (7(s)-(1alpha,2beta,4beta,5alpha,7beta))-

2.3.3 Other Synonyms

1. Scopolamine Sulfate

2. Scopolamine Sulphate

2.4 Create Date
2005-06-29
3 Chemical and Physical Properties
Molecular Weight 303.35 g/mol
Molecular Formula C17H21NO4
XLogP30.9
Hydrogen Bond Donor Count1
Hydrogen Bond Acceptor Count5
Rotatable Bond Count5
Exact Mass303.14705815 g/mol
Monoisotopic Mass303.14705815 g/mol
Topological Polar Surface Area62.3 Ų
Heavy Atom Count22
Formal Charge0
Complexity418
Isotope Atom Count0
Defined Atom Stereocenter Count5
Undefined Atom Stereocenter Count0
Defined Bond Stereocenter Count0
Undefined Bond Stereocenter Count0
Covalently Bonded Unit Count1
4 Drug and Medication Information
4.1 Therapeutic Uses

Adjuvants, Anesthesia; Antiemetics; Muscarinic Antagonists; Mydriatics; Parasympatholytics

National Library of Medicine's Medical Subject Headings online file (MeSH, 1999)


Although transdermal scopolamine has been shown to decrease basal acid output and inhibit betazole-, pentagastrin-, and peptone-stimulated gastric acid secretion in healthy individuals, it has not been determined whether transdermal scopolamine is effective in the adjunctive treatment of peptic ulcer disease. /Use is not currently included in the labeling approved by the US FDA/

American Society of Health System Pharmacists. AHFS Drug Information 2008. Bethesda, Maryland 2008, p. 1321


Transdermal scopolamine has shown minimal antiemetic activity against chemotherapy-induced vomiting. /Use is not currently included in the labeling approved by the US FDA/

American Society of Health System Pharmacists. AHFS Drug Information 2008. Bethesda, Maryland 2008, p. 1321


Scopolamine hydrobromide is used as a mydriatic and cycloplegic, especially when the patient is sensitive to atropine or when less prolonged cycloplegia is required. The effects of the drug appear more rapidly and have a shorter duration of action than those of atropine. Scopolamine hydrobromide is also used in the management of acute inflammatory conditions (i.e., iridocyclitis) of the iris and uveal tract. /Scopolamine hydrobromide/

American Society of Health System Pharmacists. AHFS Drug Information 2008. Bethesda, Maryland 2008, p. 2912


For more Therapeutic Uses (Complete) data for SCOPOLAMINE (10 total), please visit the HSDB record page.


4.2 Drug Warning

The use of scopolamine to produce tranquilization and amnesia in a variety of circumstances, including labor, is declining and of questionable value. Given alone in the presence of pain or severe anxiety, scopolamine may induce outbursts of uncontrolled behavior.

Hardman, J.G., L.E. Limbird, P.B., A.G. Gilman. Goodman and Gilman's The Pharmacological Basis of Therapeutics. 11th ed. New York, NY: McGraw-Hill, 2006., p. 197


Scopolamine in therapeutic doses normally causes CNS depression manifested as drowsiness, amnesia, fatigue, and dreamless sleep, with a reduction in rapid eye movement (REM) sleep. It also causes euphoria and is therefore subject to some abuse. The depressant and amnesic effects formerly were sought when scopolamine was used as an adjunct to anesthetic agents or for preanesthetic medication. However, in the presence of severe pain, the same doses of scopolamine can occasionally cause excitement, restlessness, hallucinations, or delirium. These excitatory effects resemble those of toxic doses of atropine.

Hardman, J.G., L.E. Limbird, P.B., A.G. Gilman. Goodman and Gilman's The Pharmacological Basis of Therapeutics. 11th ed. New York, NY: McGraw-Hill, 2006., p. 191-2


Scopolamine-induced inhibition of salivation occurs within 30 minutes or within 30 minutes to 1 hour and peaks within 1 or 1-2 hours after IM or oral administration, respectively; inhibition of salivation persists for up to 4-6 hours. Following IV administration of a 0.6-mg dose in one study, amnesia occurred within 10 minutes, peaked between 50-80 minutes, and persisted for at least 120 minutes after administration. Following IM administration of a 0.2-mg dose of scopolamine in one study, antiemetic effect occurred within 15-30 minutes and persisted for about 4 hours. Following IM administration of a 0.1- or 0.2-mg dose in another study, mydriasis persisted for up to 8 hours. The transdermal system is designed to provide an antiemetic effect with an onset of about 4 hours and with a duration of up to 72 hours after application.

American Society of Health System Pharmacists. AHFS Drug Information 2008. Bethesda, Maryland 2008, p. 1323


Small doses of ... scopolamine inhibit the activity of sweat glands innervated by sympathetic cholinergic fibers, and the skin becomes hot and dry. Sweating may be depressed enough to raise the body temperature, but only notably so after large doses or at high environmental temperatures.

Hardman, J.G., L.E. Limbird, P.B., A.G. Gilman. Goodman and Gilman's The Pharmacological Basis of Therapeutics. 11th ed. New York, NY: McGraw-Hill, 2006., p. 194


For more Drug Warnings (Complete) data for SCOPOLAMINE (21 total), please visit the HSDB record page.


4.3 Drug Indication

Scopolamine is indicated in adult patients for the prevention of nausea and vomiting associated with motion sickness and for the prevention of postoperative nausea and vomiting (PONV) associated with anesthesia or opiate analgesia.


FDA Label


5 Pharmacology and Biochemistry
5.1 Pharmacology

Scopolamine is an anticholinergic belladonna alkaloid that, through competitive inhibition of muscarinic receptors, affects parasympathetic nervous system function and acts on smooth muscles that respond to acetylcholine but lack cholinergic innervation. Formulated as a patch, scopolamine is released continuously over three days and remains detectable in urine over a period of 108 hours. Scopolamine is contraindicated in angle-closure glaucoma and should be used with caution in patients with open-angle glaucoma due to scopolamine's ability to increase intraocular pressure. Also, scopolamine exhibits several neuropsychiatric effects: exacerbated psychosis, seizures, seizure-like, and other psychiatric reactions, and cognitive impairment; scopolamine may impair the ability of patients to operate machinery or motor vehicles, play underwater sports, or perform any other potentially hazardous activity. Women with severe preeclampsia should avoid scopolamine. Patients with gastrointestinal or urinary disorders should be monitored frequently for impairments, and scopolamine should be discontinued if these develop. Scopolamine can cause blurred vision if applied directly to the eye, and the transdermal patch should be removed before an MRI procedure to avoid skin burns. Due to its gastrointestinal effects, scopolamine can interfere with gastric secretion testing and should be discontinued at least 10 days before performing the test. Finally, scopolamine may induce dependence and resulting withdrawal symptoms, such as nausea, dizziness, vomiting, gastrointestinal disturbances, sweating, headaches, bradycardia, hypotension, and various neuropsychiatric manifestations following treatment discontinuation; severe symptoms may require medical attention.


5.2 MeSH Pharmacological Classification

Adjuvants, Anesthesia

Agents that are administered in association with anesthetics to increase effectiveness, improve delivery, or decrease required dosage. (See all compounds classified as Adjuvants, Anesthesia.)


Antiemetics

Drugs used to prevent NAUSEA or VOMITING. (See all compounds classified as Antiemetics.)


Cholinergic Antagonists

Drugs that bind to but do not activate CHOLINERGIC RECEPTORS, thereby blocking the actions of ACETYLCHOLINE or cholinergic agonists. (See all compounds classified as Cholinergic Antagonists.)


Muscarinic Antagonists

Drugs that bind to but do not activate MUSCARINIC RECEPTORS, thereby blocking the actions of endogenous ACETYLCHOLINE or exogenous agonists. Muscarinic antagonists have widespread effects including actions on the iris and ciliary muscle of the eye, the heart and blood vessels, secretions of the respiratory tract, GI system, and salivary glands, GI motility, urinary bladder tone, and the central nervous system. (See all compounds classified as Muscarinic Antagonists.)


Mydriatics

Agents that dilate the pupil. They may be either sympathomimetics or parasympatholytics. (See all compounds classified as Mydriatics.)


5.3 FDA Pharmacological Classification
5.3.1 Active Moiety
SCOPOLAMINE
5.3.2 FDA UNII
DL48G20X8X
5.3.3 Pharmacological Classes
Cholinergic Antagonists [MoA]; Anticholinergic [EPC]
5.4 ATC Code

A04AD01

S76 | LUXPHARMA | Pharmaceuticals Marketed in Luxembourg | Pharmaceuticals marketed in Luxembourg, as published by d'Gesondheetskeess (CNS, la caisse nationale de sante, www.cns.lu), mapped by name to structures using CompTox by R. Singh et al. (in prep.). List downloaded from https://cns.public.lu/en/legislations/textes-coordonnes/liste-med-comm.html. Dataset DOI:10.5281/zenodo.4587355


A - Alimentary tract and metabolism

A04 - Antiemetics and antinauseants

A04A - Antiemetics and antinauseants

A04AD - Other antiemetics

A04AD01 - Scopolamine


N - Nervous system

N05 - Psycholeptics

N05C - Hypnotics and sedatives

N05CM - Other hypnotics and sedatives

N05CM05 - Scopolamine


S - Sensory organs

S01 - Ophthalmologicals

S01F - Mydriatics and cycloplegics

S01FA - Anticholinergics

S01FA02 - Scopolamine


5.5 Absorption, Distribution and Excretion

Absorption

The pharmacokinetics of scopolamine differ substantially between different dosage routes. Oral administration of 0.5 mg scopolamine in healthy volunteers produced a Cmax of 0.54 0.1 ng/mL, a tmax of 23.5 8.2 min, and an AUC of 50.8 1.76 ng\*min/mL; the absolute bioavailability is low at 13 1%, presumably because of first-pass metabolism. By comparison, IV infusion of 0.5 mg scopolamine over 15 minutes resulted in a Cmax of 5.00 0.43 ng/mL, a tmax of 5.0 min, and an AUC of 369.4 2.2 ng\*min/mL. Other dose forms have also been tested. Subcutaneous administration of 0.4 mg scopolamine resulted in a Cmax of 3.27 ng/mL, a tmax of 14.6 min, and an AUC of 158.2 ng\*min/mL. Intramuscular administration of 0.5 scopolamine resulted in a Cmax of 0.96 0.17 ng/mL, a tmax of 18.5 4.7 min, and an AUC of 81.3 11.2 ng\*min/mL. Absorption following intranasal administration was found to be rapid, whereby 0.4 mg of scopolamine resulted in a Cmax of 1.68 0.23 ng/mL, a tmax of 2.2 3 min, and an AUC of 167 20 ng\*min/mL; intranasal scopolamine also had a higher bioavailability than that of oral scopolamine at 83 10%. Due to dose-dependent adverse effects, the transdermal patch was developed to obtain therapeutic plasma concentrations over a longer period of time. Following patch application, scopolamine becomes detectable within four hours and reaches a peak concentration (tmax) within 24 hours. The average plasma concentration is 87 pg/mL, and the total levels of free and conjugated scopolamine reach 354 pg/mL.


Route of Elimination

Following oral administration, approximately 2.6% of unchanged scopolamine is recovered in urine. Compared to this, using the transdermal patch system, less than 10% of the total dose, both as unchanged scopolamine and metabolites, is recovered in urine over 108 hours. Less than 5% of the total dose is recovered unchanged.


Volume of Distribution

The volume of distribution of scopolamine is not well characterized. IV infusion of 0.5 mg scopolamine over 15 minutes resulted in a volume of distribution of 141.3 1.6 L.


Clearance

IV infusion of 0.5 mg scopolamine resulted in a clearance of 81.2 1.55 L/h, while subcutaneous administration resulted in a lower clearance of 0.14-0.17 L/h.


Scopolamine hydrobromide is rapidly absorbed following IM or subcutaneous injection. The drug is well absorbed from the GI tract, principally from the upper small intestine. Scopolamine also is well absorbed percutaneously. Following topical application behind the ear of a transdermal system, scopolamine is detected in plasma within 4 hours, with peak concentrations occurring within an average of 24 hours. In one study in healthy individuals, mean free and total (free plus conjugated) plasma scopolamine concentrations of 87 and 354 pg/mL, respectively, have been reported within 24 hours following topical application of a single transdermal scopolamine system that delivered approximately 1 mg/72 hours. /Scopolamine hydrobromide/

American Society of Health System Pharmacists. AHFS Drug Information 2008. Bethesda, Maryland 2008, p. 1323


Following oral administration of a 0.906-mg dose of scopolamine in one individual, a peak concentration of about 2 ng/mL was reached within 1 hour. Although the commercially available transdermal system contains 1.5 mg of scopolamine, the membrane-controlled diffusion system is designed to deliver approximately 1 mg of the drug to systemic circulation at an approximately constant rate over a 72-hour period. An initial priming dose of 0.14 mg of scopolamine is released from the adhesive layer of the system at a controlled, asymptotically declining rate over 6 hours; then, the remainder of the dose is released at an approximate rate of 5 ug/hour for the remaining 66-hour functional lifetime of the system. The manufacturer states that the initial priming dose saturates binding sites on the skin and rapidly brings the plasma concentration to steady-state. In a crossover study comparing urinary excretion rates of scopolamine during multiple 12-hour collection intervals in healthy individuals, there was no difference between the rates of excretion of drug during steady-state (24-72 hours) for constant-rate IV infusion (3.7-6 mcg/hour) and transdermal administration. The transdermal system appeared to deliver the drug to systemic circulation at the same rate as the constant-rate IV infusion; however, relatively long collection intervals (12 hours) make it difficult to interpret the data precisely. During the 12- to 24-hour period of administration and after 72 hours, the rate of excretion of scopolamine was higher with the transdermal system than with the constant-rate IV infusion.

American Society of Health System Pharmacists. AHFS Drug Information 2008. Bethesda, Maryland 2008, p. 1323


The distribution of scopolamine has not been fully characterized. The drug appears to be reversibly bound to plasma proteins. Scopolamine apparently crosses the blood-brain barrier since the drug causes CNS effects. The drug also reportedly crosses the placenta and is distributed into milk..

American Society of Health System Pharmacists. AHFS Drug Information 2008. Bethesda, Maryland 2008, p. 1323


Although the metabolic and excretory fate of scopolamine has not been fully determined, the drug is thought to be almost completely metabolized (principally by conjugation) in the liver and excreted in urine. Following oral administration of a single dose of scopolamine in one study, only small amounts of the dose (about 4-5%) were excreted unchanged in urine within 50 hours; urinary clearance of unchanged drug was about 120 mL/minute. In another study, 3.4% or less than 1% of a single dose was excreted unchanged in urine within 72 hours following subcutaneous injection or oral administration of the drug, respectively. Following application of a single transdermal scopolamine system that delivered approximately 1 mg/72 hours in healthy individuals, the urinary excretion rate of free and total (free plus conjugated) scopolamine was about 0.7 and 3.8 ug/hour, respectively. Following removal of the transdermal system of scopolamine, depletion of scopolamine bound to skin receptors at the site of the application of the transdermal system results in a log-linear decrease in plasma scopolamine concentrations. Less than 10% of the total dose is excreted in urine as unchanged drug and its metabolites over 108 hours.

American Society of Health System Pharmacists. AHFS Drug Information 2008. Bethesda, Maryland 2008, p. 1323


5.6 Metabolism/Metabolites

Little is known about the metabolism of scopolamine in humans, although many metabolites have been detected in animal studies. In general, scopolamine is primarily metabolized in the liver, and the primary metabolites are various glucuronide and sulphide conjugates. Although the enzymes responsible for scopolamine metabolism are unknown, _in vitro_ studies have demonstrated oxidative demethylation linked to CYP3A subfamily activity, and scopolamine pharmacokinetics were significantly altered by coadministration with grapefruit juice, suggesting that CYP3A4 is responsible for at least some of the oxidative demethylation.


Although the metabolic and excretory fate of scopolamine has not been fully determined, the drug is thought to be almost completely metabolized (principally by conjugation) in the liver and excreted in urine.

American Society of Health System Pharmacists. AHFS Drug Information 2008. Bethesda, Maryland 2008, p. 1323


5.7 Biological Half-Life

The half-life of scopolamine differs depending on the route. Intravenous, oral, and intramuscular administration have similar half-lives of 68.7 1.0, 63.7 1.3, and 69.1 8/0 min, respectively. The half-life is greater with subcutaneous administration at 213 min. Following removal of the transdermal patch system, scopolamine plasma concentrations decrease in a log-linear fashion with a half-life of 9.5 hours.


Following application of a single transdermal scopolamine system that delivered approximately 1 mg/72 hours, the average elimination half-life of the drug was 9.5 hours.

American Society of Health System Pharmacists. AHFS Drug Information 2008. Bethesda, Maryland 2008, p. 1323


5.8 Mechanism of Action

[Acetylcholine] (ACh) is a neurotransmitter that can signal through ligand-gated cation channels (nicotinic receptors) and G-protein-coupled muscarinic receptors (mAChRs). ACh signalling via mAChRs located in the central nervous system (CNS) and periphery can regulate smooth muscle contraction, glandular secretions, heart rate, and various neurological phenomena such as learning and memory. mAChRs can be divided into five subtypes, M1-M5, expressed at various levels throughout the brain. Also, M2 receptors are found in the heart and M3 receptors in smooth muscles, mediating effects apart from the direct modulation of the parasympathetic nervous system. While M1, M3, and M5 mAChRs primarily couple to Gq proteins to activate phospholipase C, M2 and M4 mainly couple to Gi/o proteins to inhibit adenylyl cyclase and modulate cellular ion flow. This system, in part, helps to control physiological responses such as nausea and vomiting. Scopolamine acts as a non-selective competitive inhibitor of M1-M5 mAChRs, albeit with weaker M5 inhibition; as such, scopolamine is an anticholinergic with various dose-dependent therapeutic and adverse effects. The exact mechanism(s) of action of scopolamine remains poorly understood. Recent evidence suggests that M1 (and possibly M2) mAChR antagonism at interneurons acts through inhibition of downstream neurotransmitter release and subsequent pyramidal neuron activation to mediate neurological responses associated with stress and depression. Similar antagonism of M4 and M5 receptors is associated with potential therapeutic benefits in neurological conditions such as schizophrenia and substance abuse disorders. The significance of these observations to scopolamine's current therapeutic indications of preventing nausea and vomiting is unclear but is linked to its anticholinergic effect and ability to alter signalling through the CNS associated with vomiting.


Although other antimuscarinics have been used in the prevention of motion sickness, it appears that scopolamine is most effective. Scopolamine apparently corrects some central imbalance of acetylcholine and norepinephrine that may occur in patients with motion sickness. It has been suggested that antimuscarinics may block the transmission of cholinergic impulses from the vestibular nuclei to higher centers in the CNS and from the reticular formation to the vomiting center; these effects result in prevention of motion-induced nausea and vomiting.

American Society of Health System Pharmacists. AHFS Drug Information 2008. Bethesda, Maryland 2008, p. 1323


The sole active agent of Transderm Scoop is scopolamine, a belladonna alkaloid with well known pharmacological properties. It is an anticholinergic agent which acts: i) as a competitive inhibitor at postganglionic muscarinic receptor sites of the parasympathetic nervous system, and ii) on smooth muscles that respond to acetylcholine but lack cholinergic innervation. It has been suggested that scopolamine acts in the central nervous system (CNS) by blocking cholinergic transmission from the vestibular nuclei to higher centers in the CNS and from the reticular formation to the vomiting center.

Thomson Health Care Inc.; Physicians' Desk Reference 62 ed., Montvale, NJ 2008, p. 2192